Swedish botanist Carl Linnaeus (1707–1778) defined only two kingdoms for organisms in 1735 – animals and ‘vegetables’ (plants). But mushrooms are not plants : they cannot make their own food.
Soon after, the microscope ushered in discoveries that ultimately led to the six recognized kingdoms of living creatures today :
Bacteria (bacteria; their cells have no nucleus),
Protista (single-cell organisms),
Plantae (plants, shrubs and giant Sequoia trees),
Fungi (mushrooms, yeasts, molds) and
Animalia (worms, insects, birds, fish, whales, salt-water sponges, star fish, sea cucumbers, animals and humans*). *Yes, we are animals, every one of us!
I suppose when alien creatures from outer space land on Earth we can add a seventh kingdom !